Solved Double clicking fails to open a 7-Zip file

I was trying to make some changes to7-Zip file associations and have managed to lose the ability to open a 7-Zip file (with a .7z extension) by double clicking it with the left mouse button. All other operations work fine. I can open a file from the main program. I can right click it to get into the 7-Zip context menu and open it, either directly, or by using "open with" (which tells me that...